Segmented stator ring assembly



Dec. 15, 1959 N. KLoMPAs ETAL 2,917,276

SEGMENTED sTAToR RING ASSEMBLY Filed Aug. 22, 1955 5 Sheets-Sheet l mveNrovg NICHOLAS KLOMPAS JOSEPH THOMPSON PURVIS YWHW A fro @bays Dec. 15, 1959 N. KLoMPAs x-:TAL

sEGMENTx-:D sTAToR RING ASSEMBLY 5 Sheets-Sheet l2 Filed Aug. 22, 1955 n n n n r BY JOSEPH THOMPSON 9URV|S 3 Sheets-Sheet 3 NveNTorLs Lompns N PURvlS Arromyeys.

NICHOLAS N. KLOMPAS ET AL SEGMENTED STATOR RING ASSEMBLY JOSEVH THOMPSO Dec. 15, 1959 Filed Aug. 22, 1955 United States Patent'O SEGNIENTED .STATOR RING ASSEMBLY 1 Nicholas Klompas, North York Township, and Joseph Thompson Purvis, Etobicoke Township, Ontario, Canada, assignors to (Brenda Engines Limited, Malton,

- Ontario, Canada, a corporation l a multiple-stage turbine.

The assembly of multiple-stage turbines in gas' turbine engines normally requires the installation of avring of' stator blades between two rotor stages. In known constructions, this means that the stator blades must be installed before the secondary or rearward rotor stage can be put in place. And dis-assembly 'of the stator ring in a `twin-stage turbine requires removal of the secondary rotor stage, which is a time-consuming operation.

.The principal object of this invention is to provide a stator blade assembly which (a) may be installed between fully assembled rotor stages and (b) may be easily assembled and dis-assembled for servicing in a' twin turbine or other multiple turbine engine without removal of a turbine rotor. f

The further object of the invention is to achieve a particularly light construction of stator blading.

A further object of the invention is to eliminate the necessity for dis-assembling a multiple-turbine rotor after it has been balanced prior to assembly of the engine.

According to the invention, in a gas: turbine engine having front and rear rotor stages connected together,

there is provided a front rotor shroud ring encircling the front rotor stage, a front outer casing encircling the front f rotor shroud ring, a stator ring assembly between the rotor stages and comprising stator ring segments in end-v to-end relationship, each segment comprising a section of an outer shroud ring, a section of an inner shroud ring and stator blades rigidly secured between said sections; each section of the outer shroud ring comprising a central portion having at its front and rear edges outwardly extending radial flanges, a forwardly extending clamping ange on the front radial ange engaged with the front outer casing, inner and outer rearwardly extending clamping flanges on the rear radial ange, a segmented rear rotor-shroud ring encircling the rearA rotor stage, a forwardly facing groove at the front end of the rear rotor shroud ring engaged by said inner rearwardly extending clamping ange, a rearwardly facing groove at the rear end of the rear rotor shroud ring, an outer casing ring comprising a central portion which encircles both the stator ring assembly and the rear rotor shroud ring, is spaced radially outwardly of the central portions of the sections of the outer shroud ring and of the rear rotor shroud ring, and extends axially from the rear end of the front outer casing to the rear end of the rear rotor shroud ring, the outer casing ring being peripherally conilange of the outer casing ring with the corresponding clamping flanges on the outer shroud ring sections and the groove in the rear rotor shroud ring respectively.

In the drawingsin which each reference character lindicates the same part in all the views:

Fig. 1 is a side elevation of a typical gas turbine. It is partly broken away to show in section a segmental stator blade shroudring according to the invention.

Fig. 2 is a perspective View, partly broken away, of

a shroud ring segment.

Fig. 3 is a section taken on a plane passing through the axis of a turbine; it shows the segmental shroud ring and attached stator blades between two rotors.

rFig. 4 is a sectional View like Fig. 3 but showing the parts in spaced relationship ready for assembly.

Fig. 5 is a radial section taken on the line 5 5 in Fig. 4,` and Fig. 6 is an enlarged sectional view of the outer part of the stator ring assembly according to the invention.

The form of the invention shown in the drawings is suitable for use in a gas turbine engine like that shown the-turbine 11 to rotate the primary (front) and secondary (rear) zrotors 14 and 15 respectively. y

The rotors 14 and 15 are secured together by kbolts 16 or by other suitable means, and each carries a ring of radially extending rotor blading 17. Between the two rings of rotor blading is a stator ring including a ring of stator blading with radially inwardly extending blades 18, each of which is fastened at its outer end to an outer shroud ring 19 and at its inner end to an inner shroud ring 20.

The outer and inner-shroud rings 19 and 20 are divided into short sections with the outer sections in radial registration with the inner ones. (in the example of the invention shown in the drawings).

tive of the stator blades 18. One outer and one inner'A shroud ring section connected by the live stator blades form a stator shroud ring segment 21. The stator ring a forwardly extending clamping ilange 24, and the rear i ange 23 has -a similar, but rearwardly extending, outer clamping flange 25. The clamping anges 24 and 25 are at the outer edges of the radial anges 22 and 23. The rear radial flange 23 also has an inner rearwardly extending clamping flange 26 near its inner edge; in effect this is a rearward continuation of the outer shroud ring Stiiening ribs or fins 27 are provided on the web of the outer shroud ring 19 between the flanges 21 and 23. Each of the inner shroud ring sections 20 -is reinforced by a rib section 28 for the same purpose; it is welded to the inner face of the ring section.

Each 'section carries Each inner shroud ring section 20 also has a spacing channel 29 having flanged upper edges 29a welded to the ring section. The inner face 29h of the channel carries a stationary labyrinth seal; it is formed of thin flanged ns 36 welded to the inner face of the channel and cooperates with the spacing disc 39a between the rotors.

When assembled, the stator shroud ring assembly lies immediately behind a front rotor shroud ring 31 and a front outer casing 32.

The front rotor shroud ring has a thickened rear edge carrying a groove 31a, and the front outer casing 32 has a bolting llange 32a extending radially outward and an inner ange 3..b extending radially inward. At its bottom edge, the inner flange has a circumferential clamping flange 32c extending forward, whcih is engaged by the groove 31a in the edge of the front rotor shroud ring 31.

There is a thickened part 32d adjacent the bolting flange 32b on the front outer casing 32 and this carries pushfitted pins 33 angularly spaced on the circumference so that each coincides with the center of one of the outer stator shroud sections 19 when its stator segment 21 is in place. The flange 23 on each outer stator shroud section has a notch 23a adapted to receive the end of one of the pins 33.

The cylindrical surface of the outer shroud ring 19 is continued rearward by a segmented rear rotor shroud ring 33. In assembling the stator shroud ring assembly, each segment 21 is secured to a section of the rear rotor shroud ring corresponding in circumferential length to the sections of the outer stator shroud ring.

The rear rotor shroud ring has thickened front and rear` edges carrying grooves 33a and 33h; the front groove 33a receives the inner rearwardly extending clamping flange 26 on the outer shroud ring 19 so that the two sections can be secured together by radial pins 34 which extend through holes in the thickened front edge of the rear rotor shroud, and through the flange 26 on the outer shroud ring.

At the rear edge of the rear rotor shroud ring 33, the groove 33b in the thickened part faces rearward. Encircling the outer shroud ring and rear rotor shroud ring is an outer casing ring 35 comprising a central portion which has a forward flange 35a adapted to engage the front outer casing bolting flange 32a and to be secured to it by bolts 36 over they front clamping flange 24 on the outer shroud ring. At the rear of the central portion of the outer casing ring 35 is another arrangement of llanges 35h, one of. which engages the rearward facing groove 331. The outer casing ring is perpherally continuous throughout at least half of its periphery and may conveniently be peripherally continuous throughout its whole periphery.

Inside the central portion of the outer casing ring 35 is an annular right angled flange 35e-providing a forwardfacing groove receiving the outer clamping flange 25 at the rear of the outer shroud ring 19.

The pins 34 securing the outer shroud ring to the rear rotor shroud ring are sulllciently long that the rightangled ilange 35c on the outer casing ring, when the latter is installed, just clears the radially outer ends of the pins. In this way the pins are held in place.

The outer casing ring 35 is adapted to be installed by' being passed forwardly over the turbine into engagement with the bolting flange 32a, the groove 33h and the clamping flanges 24 and 25. Behind it is a rear outer casing continuation 37 and a tail cone 3S, with a bolting flange 39 to which one of the rear flanges of the outer casing ring 35 is secured by bolts 40.

In each ofthe stator shroud ring segments 21 the ends of the stator blades are brazed or welded to the outer and inner stator shroud rings 19 and Ztl. The rib section 28. is fastened in the same way to the inner face of the inner shroud ring section. The spacing channel is brazed or welded to the inner face of the ring section and ns 30 are similarly secured to the inner face of the channel.

Each blade has at its inner and outer ends root flanges 18a and 18b respectively. In the preferred construction according to the invention, shaped openings are provided in the inner shroud ring sections 20 and in the liners 19b of the outer shroud ring sections 19 to receive these root flanges within the liner thickness. The level joint thus made is secured by brazing, additional metal being used to ll any space left in the openings. To simplify the assembly, the blades may be attached temporarily by spot welding before the actual brazing operation.

For added strength, the top and bottom faces of the root flanges are welded directly to the main outer shroud ring sections 19a and to the rib section 23 on the inner shroud ring 20.

(An alternative Way of fastening the parts of the segment 21 is by welding the faces of the root flanges to the inside face of the outer shroud ring section 19 and to the outside face of the inner shroud section to produce a conventional butt joint.)

Both ends of each of the outer stator shroud ring sections 19 have either protruding flanges 4l, or recesses 42 to receive the anges 41, so that when the stator shroud ring is assembled one'of each pair of the outer shroud ring sections overlaps the adjacent end of the other section of the pair,'the joints between the segments 21 are covered by the llanges 41 and an airtight ring is produced. s

The ilanges 41are produced by extending the liners 19b beyond the ends of the main stator shroud ring sections 19a and the recesses 42 are produced by letting the main sections 19a extend beyond the ends of the liner sections. in Fig. 5, thesegments having ilanges are indicated as 21A and those having recesses as 21B.

When the engine is to be assembled, the engine is preferably placed nose-downward. Before the outer casing ring 35 or the rear casing and tail cone assemblyv are installed, the stator shroud ring assembly is completed by inserting the segments 21 with attached rear rotor shroud ring sections 33 between 'the' rotor stages. The segments 21A (with ilanges 41) are inserted first, and an equal number of the segments 21B (with recesses 42) are then inserted between each pair of segments 21A. When the rotor shroud ring assembly is complete, the outer casing ring 35, with the rear outer casing and tail cone assembly preferably attached to it, is slid downward over the turbine, clamping the stator and rear rotor shroud rings in place. Fastening the bolts 36 completes the assembly. It will be seen that the central portion of theouter shroud ring encircles, and is spaced from, both the central portion of the outer shroud ring 19 and also the rear rotor shroud ring 33.

While a preferred embodiment of the invention has been described it is to be appreciated that modifications and alterations may be made within the spirit and scope of the invention as dened in the following claims.

What we claim as our invention is:

l. In a gas turbine engine, front and rear rotor stages connected together, a front rotor shroud ring encircling the front rotor stage, a front outer casing encircling the front rotor shroud ring, a stator ring assembly between the rotor stages and comprising stator ring segments in end-to-end relationship, each segment comprising a section of an outer shroud ring, a section of an inner shroud ring and stator blades rigidly secured between said sections; each section of the outer shroud ring comprising a central portion having at its front and rear edges outwardly extending radial flanges, a forwardly extending clamping flange on the front radial flange engaged with the front outer casing, inner and outer rearwardly extending clamping flanges on the rear radial flange, a segmented rear rotor shroud ring encircling the rear rotor stage, a forwardly facing groove at Ythe front end of the rear rotor shroud ring engaged by said inner rearwardly extending, clamping flange, a rearwardly facing groove at theA rear end of the rear rotor shroud ring, an outer casing ring comprising a central portion lwhich encircles both the .stator ring. assembly and the rear rotor' slfoud ring,y isspaced radially VN(nitwa'rdlylof the centralV portions of the sections of theout'er shroud ring and of the rear rotor shroud ring, and extends axially from the rear end of the front outer casing to the rear end of the rear rotor shroud ring, the outercasing ring being peripherally continuous throughout a major portion of its periphery; an inwardly extending radial flange at the rear end of the central portion of the outer casing ring, a forwardly extending clamping flangeon said'radial flange engaged in the rearwardly facing groove of the rear rotor shroud ring, a forwardly facing groove on the outer casing ring engaged with the outer rearwardly facing clamping flanges on theouter shroud ring sections, and means securing the forward end ofthe outer casing ring to the-rear end of the front outer casing, the outer casing ring being arranged to be passed, during assembly of the gasv turbine engine, forwardly over the previously assembled stator ring assembly and vrear rotor shroud to engage the front outer casing andengage the groove and clamping flanges on the outer shroud ring sections and the groove in the rear rotor shroudring respectively.

2. In a gas turbine engine, front and rear rotor stages connected together, a front rotorv shroud ring encircling the front rotor stage, a front outer casing encircling the front rotor shroud ring, a stator vring assembly between the rotor stages and comprising stator ring segments in end-to-end relationship, each segment comprising a section of an outer shroud ring, a section of an inner shroud ring and stator blades rigidly secured between said sections; each section of the outer shroud ring comprising a central portion having at its front and rear edges outwardly extending radial flanges, a forwardly extending clamping flange on the front radial flange engaged with the frontA outer casing, inner and outer rearwardly extending clamping flanges on the rear radial flange, a segmented rear rotor shroud ring encircling the rear rotor stage, a forwardly facing groove at the front end of the rear rotor shroud ring engaged by said inner rearwardly extending clamping flange, a rearwardly facing groove at the rear end Vof the rear rotorshroud ring, an outer casing ringcomprising a central portion which encircles both the stator ring assembly and the rear rotor shroud ring, is spaced radiallyoutwardly of the central portions of the sections of the outer shroud ring and of the rear rotor shroud ring,v and extends axially from the rear end of the front outer Acasing to the rear end of the rear rotor shroud ring, the outer casing ring being peripherally -continuous throughout the major portion of its periphery; an inwardly extending radial flange at the rear end of the central portion of the outer casing ring, a forwardly extending clamping flange on said radial flange engaged by the rearward-ly facing groove of the rear rotor shroud ring, a forwardly facing groove on the outer casing ring engaged with the outer` rearwardly facing clamping flanges on the outer shroud ring sections, radially extending pins passing through apertures in the outer wall of the groove at the forward end of the rear rotor shroud ring and into apertures in the clamping flange engaged therein, the pins extending outwardly to terminate adjacent to the inner wall of the forwardly facing groove on the outer casing ring, and means securing the forward end of the outer casing ring to the rear end of the front outer casing, the outer casing ring being arranged to be passed, during assembly of the gas turbine engine, forwardly over the previously assembled stator ring assembly and rear rotor shroud to engage the front outer casing and engage the groove and clamping flange of the outer casing ring with the corresponding clamping flanges on the outer shroud ring sections and the groove in the rear rotor shroud ring respectively.

3. In a gas turbine engine, front and rear rotor stages connected together, a front rotor shroud ring encircling the front rotor stage, a front outer casing encircling the front rotor shroud ring, an inwardly extending radial flange on the front outer casing, a forwardly extending clamping flange at the inner periphery of said radialk flange, a rearwardly facing groove in the front rotor shroud ring engaged' with said forwardly extending clamping flange, a stator ring assembly between the rotor stages and comprising stator ring segments in end-to-end relationship, each segment comprising a section of an outer t shroud ring, a section of an inner shroud ring and stator blades rigidly secured between said sections; each section 'of the outer shroud ring comprising a central por-v tion having at its front and rear edges outwardly extending radial flanges, a forwardly extending clamping flange on the front radial flange engaged with the front outer casing, inner and outer rearwardly extending clamping flanges on the rear radial flange, a segmented rear rotor shroud ring encircling the rear rotor stage, a forwardly facing groove at the front end of the rear rotor shroud ring engaged by said inner rearwardly extending clamping flange, a rearwardly facing groove at the rear end of the rear rotor shroud ring, an outer casing ring comprising a central portion which encircles both the stator ring assembly and the rear Irotor shroud ring, is spaced radially outwardly of the central portions of the sections of the outer shroudring and of the rear rotor shroud ring, and extends axially from the rear end of the front outer casing to the rear end of the rear rotor shroud ring, the outer casing ring being peripherally continuous throughout a major portion of its periphery; an inwardly extending radial flange at the rear end of the central portion of the outer casing ring, a forwardly extending clamping flange on said radial flange engaged in the rearwardly facing groove of the rear rotor shroud ring, a

forwardly facing groove on the outer casing ring engaged with the outer rearwardly facing clamping flanges on the outer shroud ring sections, and means securing the forward end of the outer casing ring to the rear end of the front outer casing, the outer casing ring being arranged to be passed, during assembly of the gas turbine engine, forwardly over the previously assembled stator ring assembly and rear rotor shroud to engage the front outer casing and engage the groove and clamping flange of the outer casing ring with the corresponding clamping flanges on the outer shroud ring sections and the groove in the rear rotor shroud ring respectively.

4. In a gas turbine engine, front and rear rotor stages y connected together, a front rotor shroud ring encircling the front rotor stage, a front outer casing encircling the.

front rotor shroud ring, an inwardly extending radial flange on the front outer casing, a forwardly extending clamping flange at the inner periphery of said radial flange, a rearwardly facing groove in the front rotor shroud ring engaged with said forwardly extending clamping flange, a stator ring assembly between the rotor stages and comprising stator ring segments in end-to-end relationship, each segment comprising a section of an outer shroud ring, a section of an inner shroud ring and stator blades rigidly secured between said sections; each section of the outer shroud ring comprising a central portion having at its front and rear edges outwardly extending radial flanges, a forwardly extending clamping flange on the front radial flange engaged with the front outer casing, inner and outer rearwardly extending clamping flanges on the rear radial flange, a segmented rear rotor shroud ring encircling the rear rotor stage, a forwardly facing groove at the front end of the rear rotor shroud ring engaged by said inner rearwardly extending clamping flange, a rearwardly facing groove at the rear end of the rear rotor shroud ring` an outer casing ring comprising a central portion which encircles both the stator ring assembly and the rear rotor shroud ring, is spaced radially outwardly of the central portions of the sections of the outer shroud ring and of the rear rotor shroud ring, and extends axially from the rear end of the front outer casing to the rearl end of the rear rotor shroud ring, the outer casing ring being peripherally continuous throughout a major portion of its periphery; an inwardly extending radial flange at the rear end of the central' portionof the outer casing ring, a forwardly extending clamping flange on said radial flange engaged in the rearwardly facing grooveof the rear rotor shroud ring, a forwardly facing groove on the outer casing ring engaged with the outer rearwardly facing clamping ilanges on the outer shroud ring sections, radially extending pins received in apertures in the front outer casing, passing through apersembled stator ring assembly and rear rotor shroud to engage the front outer casing and engage the groove and clamping flange of the outer casing ring with the corresponding clarnping flanges on the outer shroud ring sections and the groove in the rearrrotor shroud ring respectively.

5. In a gas turbine engine, front and rear rotor stages connected together, a front rotor shroud ring encircling the front rotor stage, a front outer casing encircling the front rotor shroud ring, an inwardly extending radial flange on the front outer casing, a forwardly extending clamping flange at the inner periphery of said radial ange, a rearwardly facing groove in the front rotor shroud ring engaged with said forwardly extending clamping flange, a stator ring assembly between the rotor stages and comprising stator ring segments in end-to-end relationship, each segment comprising a section of an outer shroud ring, a sectionof an inner shroud ring and statorV blades rigidly securedbetween said sections; each section ofthe outer shroud ring being formed with a channel on its inner surface, a shroud ring liner in said channel, the liner in the channel of alternate sections extending beyond the ends of the sections and into the channels of adjacent sections, the liner in each of said adjacent sections terminating short of the ends of the section, each section of the outer Ashroud ring also comprising a central portion having at its front and rear edges outwardly extending radial anges, a forwardly extending clamping flange on the front radial flange engaged with the front outer casing, inner and outer rearwardly extending clamping flanges on the rear radial ange, a segmented rear rotor shroud ringA encircling the rear rotor stage, a forwardly facing groove at the front end ofthe rear rotor shroud ring engaged by said inner rearwardly extending clamping flange, a rearwardly facing groove at the rear end ofA the-- rear rotor shroud ring, an outer casing ring comprising a,

central portion which encircles both the stator ring assent- A bly and the rear rotor shroud ring, is spaced radially outwardlyV of the central portions ofthe sections ofthe outerA shroud ring and of the rear rotor shroud ring, and ex-. tends axially from the rear end of the front outer casing to the rear end of the rear rotor shroud ring, the outerv v casing ring being peripherally continuous throughout a major portion of its periphery; an inwardly extendingv radial ange at the rear end of the central portion of the-- outer casing ring, a forwardly extending clamping flange on said radial flange engaged in the rearwardly facing groove of the rear rotor shroud ring, a forwardly facinggroove on the outer casing ring engaged with the outer rearwardly facing clamping flangeson the outer shroud ring sections, and means securing the forward end ofthe outer casing ring to the rear end of the front outer casing,l

the outer casing ring being arranged to be passed, during assembly of the gas turbine engine, forwardly over the previously assembled stator ringassembly and rear rotor shroud to engage thefront outer casing and engage the groove and clamping flange of the outer casing ring with the corresponding clamping anges on the outer shroud ring sections and the groove in the rear rotor shroud ringrespectively.

References Cited in the file of this patent UNITED STATES PATENTSy 2,110,679 Robinson Mar. 8, 193,8. 2,488,867 Judson Nov. 22, 19.49 2,584,899 McLeod Feb. 5, 1952, 2,639,579 Willgoos May 26, 1953 2,640,679 Wheatley et al June 2, l953 2,710,523 Purvis lune 14,.1955,

FOREIGN" PATENTS 491,575 Canada Mar. 24, 1953 572,859 Great Britain Oct. 26, 1945 586,562 Great Britain Mar, 24, 1947 660,383 Great Britain Nov, 7, 195,1 679,916 Great Britain Sept. 24, 1952k 689,270 Great Britain Mar. 25, 1953 715,145y Great Britain Sept. 8, 1954 723,505 Great Britain Feb. 9, 1955,V 823,442 France Oct. 18, 1937 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 2v9l7 276 December l5i i959 Nicholas Klompas etal.,

lt is hereby Certified that error appears in the printed specification of the above numbered patent requiring Correction and that the said Letters Patent should read as Corrected belowo Column 5 line 2OY before "Clamping flanges" insert Clamping flange of the outer casing ring with the Corresponding-m.,

Signed and sealed this 5th day of July 1960.,

(SEAL) Attest:

KARL H AXLNE f ROBERT C. WATSON` Attesting Officer Conmissioner of Patents 

